In a sunlit clearing amid a stand of tall sago palms in central Gondwana, one as yet quite unexceptional Tyrannosaurus rex had just lynched a plump, good-sized lizard for its midday meal. With its fearsome claws it ripped the still wriggling lizard in two and tossed the tail end into its gaping jaws. As it munched away with relish, the dinosaur felt entirely happy with the world and its own place within it.

Things below ground were far from calm, however. The Tyrannosaurus’s pursuit of the lizard had caused a powerful earthquake in the subterranean ant town located a mere metre from the dinosaur’s left foot. Fortunately, the town had just avoided being trampled, but now hordes of its thousand or so residents scuttled to the surface to see what had happened.

The Tyrannosaurus had blocked out more than half their sky; it was like a towering peak piercing the clouds. For the ants massed in the mountain’s shadow, it was as if the day had suddenly become overcast. They squinted up, up, high into the sky, watching as the lizard’s tail arced through the air and into the fathomless mouth of the Tyrannosaurus. They listened to the sound of the dinosaur chewing, to the cracking and rumbling that was like thunder from the heavens. On previous occasions, this thunder had often been accompanied by a heavy downpour of splintered bones and chunks of flesh. Even a light drizzle of the dinosaur’s leftovers would provide lunch for the entire town. But this Tyrannosaurus kept its mouth tightly closed, and nothing rained down from the sky. After a few moments, it tossed the other half of the lizard into its mouth. Thunder boomed overhead again, but still the shower of bones and flesh held off.

When the Tyrannosaurus had finished, it took a couple of steps back and lay down contentedly for a nap in the shade. The ground shuddered, the peak collapsed into a distant mountain range, and brilliant sunshine flooded the clearing once more. The ants shook their heads and sighed. The dry season was long this year, and life was getting harder by the day. They had already gone hungry for two days.

Just as the crestfallen critters were turning back towards the entrance to their town, another earthquake rocked the clearing. The mountain range was rolling agitatedly back and forth across the ground! The ants watched intently as the Tyrannosaurus stuck one of its monstrous claws into its mouth and began to dig furiously between its teeth. Immediately, they understood why the dinosaur could not sleep: lizard flesh had got stuck in its teeth and was getting on its nerves.

The mayor of the ant town had a sudden idea. It climbed onto a blade of grass and released a pheromone towards the colony below. As the pheromone spread, the ants understood the mayor’s meaning and passed the message on. Antennae waved as a tide of excitement swept through the crowd.